Display apparatus and method of producing the same

ABSTRACT

A display apparatus includes: a first semiconductor substrate that includes a light emitting unit and a first drive circuit, the first drive circuit driving the light emitting unit; and a second semiconductor substrate that includes a second drive circuit to be electrically connected to the first drive circuit, the second semiconductor substrate being bonded to the first semiconductor substrate.

BACKGROUND

The present disclosure relates to a display apparatus and a method ofproducing the same.

In recent years, an organic electroluminescent display apparatus(hereinafter, referred to also as “organic EL display apparatus”) usingan organic electroluminescent device (hereinafter, referred to also as“organic EL device”) has attracted attention as a display apparatus toreplace a liquid crystal a display apparatus. The organic EL displayapparatus includes a plurality of light emitting devices arranged in amatrix to constitute a pixel, and a plurality of pixel circuits thatdrives the light emitting devices in units of pixels (see, for example,Japanese Patent No. 6031954).

SUMMARY

The organic EL display apparatus needs a relatively high voltagecorresponding to the light emission voltage of the light emittingdevice. Therefore, it is necessary to secure at least a certain lengthof a gate length of the transistor driving each pixel and at least acertain distance of device separation for electrically separatingtransistors. For this reason, it has been difficult to shorten thedistance of device separation and reduce the pixel size. Alternatively,there is a problem that the area of the peripheral circuit that drives apixel circuit increases with advancement of the display apparatus, andthe panel size of the display apparatus increases.

In view of the circumstances as described above, it is desired toprovide a display apparatus capable of reducing the pixel size or panelsize, and a method of producing the same.

A display apparatus according to an embodiment of the present disclosureincludes: a first semiconductor substrate; and a second semiconductorsubstrate.

The first semiconductor substrate includes a light emitting unit and afirst drive circuit, the first drive circuit driving the light emittingunit.

The second semiconductor substrate includes a second drive circuit to beelectrically connected to the first drive circuit, the secondsemiconductor substrate being bonded to the first semiconductorsubstrate.

With the above-mentioned display apparatus, since a circuit for drivingthe light emitting unit is separately formed on the first semiconductorsubstrate and the second semiconductor substrate, it is possible toreduce the pixel size or panel size.

The first drive circuit may be a part of the pixel circuits, and thesecond drive circuit may be another part of the pixel circuits.

The first drive circuit may include a transistor that switches a signalvoltage or a power supply voltage, and the second drive circuit mayinclude a transistor that controls a current flowing to the lightemitting unit.

In this case, the second drive circuit may further include a transistorthat resets a voltage applied to the plurality of light emittingdevices.

Alternatively, the first drive circuit may include a transistor thatcontrols a current flowing to the light emitting unit, and the seconddrive circuit may include a transistor that switches a signal voltage ora power supply voltage.

In this case, the first drive circuit may further include a transistorthat resets a voltage applied to the plurality of light emittingdevices.

The first drive circuit may include a first capacitive device, and thesecond drive circuit may include a second capacitive device electricallyconnected to the first capacitive device.

Alternatively, the second drive circuit may include a first capacitivedevice and a second capacitive device electrically connected to thefirst capacitive device.

Meanwhile, the first drive circuit may be a pixel circuit thatindividually drives the plurality of light emitting devices, and thesecond drive circuit may be a peripheral circuit that supplies a signalvoltage or a power supply voltage to the pixel circuit.

The first semiconductor substrate and the second semiconductor substratemay each include a substrate body and a wiring layer, and the wiringlayer of the first semiconductor substrate may be bonded to the wiringlayer of the second semiconductor substrate.

Alternatively, the first semiconductor substrate and the secondsemiconductor substrate may each include a substrate body and a wiringlayer, and the substrate body of the first semiconductor substrate maybe bonded to the wiring layer of the second semiconductor substrate.

A method of producing a display apparatus according to an embodiment ofthe present disclosure includes:

preparing a first semiconductor substrate that includes a light emittingunit and a first drive circuit, the first drive circuit driving thelight emitting unit;

preparing a second semiconductor substrate that includes a second drivecircuit; and

electrically connecting the first drive circuit and the secondsemiconductor substrate by bonding the first semiconductor substrate andthe second semiconductor substrate to each other.

These and other objects, features and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription of best mode embodiments thereof, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view showing a configuration of a displayapparatus according to a first embodiment of the present disclosure;

FIG. 2 is a schematic side cross-sectional view of the displayapparatus.

FIG. 3 is an equivalent circuit diagram showing an example of a pixelcircuit in the display apparatus;

FIG. 4 is a schematic side cross-sectional view of main portions of thedisplay apparatus showing an example of the configuration of the pixelcircuit;

FIG. 5A is a schematic diagram describing a method of producing thedisplay apparatus;

FIG. 5B is a schematic diagram describing a method of producing thedisplay apparatus;

FIG. 5C is a schematic diagram describing a method of producing thedisplay apparatus;

FIG. 5D is a schematic diagram describing a method of producing thedisplay apparatus;

FIG. 6 is a schematic side cross-sectional view of main portions of adisplay apparatus according to a second embodiment of the presentdisclosure;

FIG. 7 is a schematic side cross-sectional view of main portions of adisplay apparatus according to a third embodiment of the presentdisclosure;

FIG. 8 is a schematic side cross-sectional view of main portions of adisplay apparatus according to a fourth embodiment of the presentdisclosure;

FIG. 9A is a schematic side cross-sectional view showing an example ofan electrical connection structure between a first semiconductorsubstrate and a second semiconductor substrate in the display apparatus;

FIG. 9B is a schematic side cross-sectional view showing an example ofthe electrical connection structure between the first semiconductorsubstrate and the second semiconductor substrate in the displayapparatus;

FIG. 10 is a conceptual diagram describing a modified example of aconfiguration of the display apparatus;

FIG. 11 is a schematic front view describing a modified example of aconfiguration of the display apparatus;

FIG. 12 is a diagram showing an appearance of a television apparatus asan electronic apparatus;

FIG. 13 is a diagram showing an appearance of a digital camera as anelectronic apparatus;

FIG. 14 is a diagram showing an appearance of a laptop personal computeras an electronic apparatus;

FIG. 15 is a diagram showing an appearance of a video camera as anelectronic apparatus;

FIG. 16 is a diagram showing an appearance of a mobile phone as anelectronic apparatus; and

FIG. 17 is a diagram showing an appearance of a head-mounted display asan electronic apparatus.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings.

First Embodiment

[Entire Configuration]

FIG. 1 is a schematic plan view showing a configuration of a displayapparatus according to a first embodiment of the present disclosure.FIG. 2 is a schematic side cross-sectional view of the displayapparatus.

Hereinafter, an organic EL display apparatus will be described as anexample of a display apparatus 100 according to this embodiment.

As shown in FIG. 2, the display apparatus 100 according to thisembodiment includes a first semiconductor substrate 101 and a secondsemiconductor substrate 102. The display apparatus 100 is configured bybonding (or stacking) the first semiconductor substrate 101 and thesecond semiconductor substrate 102 to each other.

Each of the first semiconductor substrate 101 and the secondsemiconductor substrate 102 typically includes a single crystal silicon(Si) substrate. Alternatively, each of the first semiconductor substrate101 and the second semiconductor substrate 102 includes anothersemiconductor substrate such as a SiC substrate.

As shown in FIG. 1, the first semiconductor substrate 101 includes apixel area 20 and a peripheral circuit area 30. In this embodiment, asshown in FIG. 2, the pixel area 20 is formed in the first semiconductorsubstrate 101, and the second semiconductor substrate 102, and theperipheral circuit area 30 is formed in the first semiconductorsubstrate 101.

In the pixel area 20, a light emitting unit 21 constituting a pixel anda pixel circuit 22 driving the light emitting unit 21. As will bedescribed below, the light emitting unit 21 includes a plurality oflight emitting devices 210 arranged in a matrix in the horizontaldirection (see FIG. 3). The pixel circuit 22 includes a plurality ofpixel circuits 22 corresponding to the plurality of light emittingdevices 210. Each of the pixel circuits 22 individually drives thecorresponding light emitting device 210.

Meanwhile, in the peripheral circuit area 30, a peripheral circuit thatsupplies a signal voltage or a power supply voltage to the pixel circuit22 is provided. Examples of the peripheral circuit typically include ahorizontal scanning circuit 31, a vertical scanning circuit 32, a gammavoltage generation circuit 33, a timing controller 34, a DAconverter/amplifier area 35, an interface 36, and a memory 37. As a partof the peripheral circuit, a test circuit 38 may be provided. As will bedescribed below, the horizontal scanning circuit 31 corresponds to ascanning circuit 23 and the light-emission-control-transistor controlcircuit 24, and the vertical scanning circuit 32 corresponds to the animage signal output circuit 25 (see FIG. 3).

The configuration and layout of the peripheral circuits (31 to 37)arranged in the peripheral circuit area 30 are not limited to thoseillustrated in the example, and are arbitrarily set. The pixel circuit22 and the peripheral circuits (31 to 37) are configured as a drivecircuit that controls driving of the light emitting unit 21. The drivecircuit includes a first drive circuit formed in the first semiconductorsubstrate 101, and a second drive circuit formed in the secondsemiconductor substrate 102. In this embodiment, the first drive circuitconstitutes a part of the pixel circuit 22 and the peripheral circuits(31 to 37), and the second drive circuit constitutes another part of thepixel circuit 22.

FIG. 3 is an equivalent circuit diagram showing an example of the pixelcircuit 22. In this embodiment, as the pixel circuit 22, a 4Tr-2C pixelcircuit including four transistors and two capacity units will bedescribed as an example. However, the present disclosure is not limitedthereto, and an appropriate pixel circuit such as a 3Tr-2C pixel circuitincluding three transistors and two capacity units, a 4Tr-1C pixelcircuit including four transistors and one capacity unit, and a 3Tr-1Cpixel circuit including three transistors and one capacity unit can beadopted.

As shown in FIG. 3, the pixel circuit 22 includes four transistors (adrive transistor Tr_(Drv), an image signal writing transistor Tr_(Sig),a first light-emission-control transistor Tr_(EL_C1), and a the secondlight-emission-control transistor Tr_(EL_C2)), two capacity units (afirst capacity unit C1 and a second capacity unit C2), and varioussignal lines (a scanning line SCL, a data line DTL, a first currentsupply line CSL₁, a second current supply line CSL₂, a first lightemission control line CL_(EL_C1), and a second light emission controlline CL_(EL_C2)). The pixel circuit 22 includes a plurality of pixelcircuits 22 corresponding to the plurality of light emitting devices 210constituting the light emitting unit 21.

The drive transistor Tr_(Drv) is a control transistor that controls acurrent flowing to the light emitting unit 21. The drive transistorTr_(Drv) includes one source/drain area to be connected to the anode ofthe light emitting unit 21, the other source/drain area to be connectedto one source/drain area of the first light-emission-control transistorTr_(EL_C1), and a gate to be connected to one source/drain area of theimage signal writing transistor Tr_(Sig) and one electrode of the firstcapacity unit C1.

The image signal writing transistor Tr_(Sig) is a row selectiontransistor that switches a signal voltage. The image signal writingtransistor Tr_(Sig) includes the other source/drain area to be connectedto the image signal output circuit 25 via the data line DTL, and a gateto be connected to the scanning circuit 23 via the scanning line SCL.

The first light-emission-control transistor Tr_(EL_C1) is a columnselection transistor that switches a power supply voltage. The firstlight-emission-control transistor Tr_(EL_C1) includes the othersource/drain area to be connected to a first current supply unit 26 viathe first current supply line CSL₁, and a gate to be connected to thelight-emission-control-transistor control circuit 24 via the first lightemission control line CL_(EL_C1). A drive voltage Vcc is applied to theother source/drain area of the first light-emission-control transistorTr_(EL_C1) from the first current supply unit 26.

The second light-emission-control transistor Tr_(EL_C2) is a transistorthat resets a voltage (anode voltage) applied to the light emitting unit21. The second light-emission-control transistor Tr_(EL_C2) includes onesource/drain area to be connected to the anode of the light emittingunit 21, the other source/drain area to be connected to a reset voltageline Vss, and a gate to be connected to thelight-emission-control-transistor control circuit 24 via the secondlight emission control line CL_(EL_C2).

The first capacity unit C1 and the second capacity unit C2 are connectedin series to each other. One electrode of the first capacity unit C1 isconnected to the gate of the drive transistor Tr_(Drv) and the onesource/drain area of the image signal writing transistor Tr_(Sig). Theother electrode of the first capacity unit C1 and one electrode of thesecond capacity unit C2 are connected to the other source/drain area ofthe drive transistor Tr_(Drv) and the one source/drain area of the firstlight-emission-control transistor Tr_(EL_C1). The other electrode of thesecond capacity unit C2 is connected to a second current supply unit 27via the second current supply line CSL₂. The drive voltage Vcc issupplied to the other electrode of the second capacity unit C2 from thesecond current supply unit 27.

The light emitting unit 21 is a current-driven-type self light emittingdevice whose light emission luminance changes in accordance with themagnitude of the supplied current. In this embodiment, the lightemitting unit 21 includes an organic EL device (OLED). The lightemitting unit 21 has a known configuration or structure including ananode electrode, an organic material layer, a cathode electrode, and thelike. The organic material layer has a structure in which, for example,a hole transport layer, a light emitting layer, and an electrontransport layer are stacked. The anode electrode is connected to the onesource/drain area of the drive transistor Tr_(Drv), and the onesource/drain area of the second light-emission-control transistorTr_(EL_C2). The cathode electrode is connected to a power supply lineVcath.

The display apparatus 100 may be configured to have a display area inwhich monochrome display or color display is performed. In the case ofthe configuration of color display, one pixel includes, for example,three sub-pixels (a red light emitting sub-pixel that emits red light, agreen light emitting sub-pixel that emits green light, and a blue lightemitting sub-pixel that emits blue light).

In this embodiment, the drive transistor Tr_(Drv), the image signalwriting transistor Tr_(Sig), the first light-emission-control transistorTr_(EL_C1), and the second light-emission-control transistor Tr_(EL_C2)each include a p-type channel MOSFET, and are each formed in an n-typewell formed in a p-type silicon semiconductor substrate.

Note that description of the detailed operation of the pixel circuit 22having the above-mentioned configuration is omitted because it isdescribed in, for example, Patent Literature 1. Hereinafter, details ofthe embodiment of the present disclosure will be described on the basisof the above-mentioned configuration.

[Pixel Circuit]

Subsequently, details of the pixel circuit 22 will be described. FIG. 4is a schematic side cross-sectional view of main portions of the displayapparatus 100 showing an example of the configuration of the pixelcircuit 22.

As described above, the display apparatus 100 according to thisembodiment includes a laminate of the first semiconductor substrate 101and the second semiconductor substrate 102. The first semiconductorsubstrate 101 has a display surface 101 a and a bonding surface 101 b.The display surface 101 a includes the light emitting unit 21. Thebonding surface 101 b is to be bonded to the second semiconductorsubstrate 102. The second semiconductor substrate 102 includes a bondingsurface 102 a to be bonded to the first semiconductor substrate 101.

The pixel circuit 22 is formed inside the first semiconductor substrate101 and the second semiconductor substrate 102. More specifically, thepixel circuit 22 includes a first pixel circuit 221 formed inside thefirst semiconductor substrate 101, and a second pixel circuit 222 formedinside the second semiconductor substrate 102. The first pixel circuit221 is a part of the pixel circuit 22, and the second pixel circuit 222is another part of the pixel circuit 22. The first pixel circuit 221 andthe second pixel circuit 222 are electrically connected to each otherwhen the first semiconductor substrate 101 and the second semiconductorsubstrate 102 are stacked, thereby forming the pixel circuit 22.

The first pixel circuit 221 constitutes a first drive circuit thatdrives a light emitting unit 210, and the second pixel circuit 222constitutes a second drive circuit that drives the light emitting unit210. At least one of the four transistors (Tr_(Drv), Tr_(Sig),Tr_(EL_c1), Tr_(EL_C2)) of the pixel circuit 22 described with referenceto FIG. 3 is formed in the first pixel circuit 221, and the othertransistor(s) is/are formed in the second pixel circuit 222. Similarly,at least one of the two capacity units (C1 and C2) constituting thepixel circuit 22 are formed in the first pixel circuit 221 or the secondpixel circuit 222.

The transistors formed in the first pixel circuit 221 and the secondpixel circuit 222 are not particularly limited. In this embodiment, theimage signal writing transistor Tr_(Sig) and the firstlight-emission-control transistor Tr_(EL_C1) are formed in the firstpixel circuit 221, and the drive transistor Tr_(Drv) and the secondlight-emission-control transistor Tr_(EL_C2) are formed in the secondpixel circuit 222 (see FIG. 4).

As shown in FIG. 4, the first pixel circuit 221 includes a plurality ofvias 22 v 1 and 22 v 2 as interlayer connection portions, a plurality ofwiring layers 22 w 1, and a the capacitive devices 22 c 1 and 22 c 2.

The vias 22 v 1 are electrically connected to an anode electrode 212 ofthe light emitting unit 21, and pass through the first semiconductorsubstrate 101 in the thickness direction via the plurality of wiringlayers 22 w 1 or are routed.

The vias 22 v 2 are connected to a gate electrode 22 g 1 of thetransistor (the first light-emission-control transistor Tr_(EL_C1) inthe illustrated example) and the respective source/drain areas.

The capacitive devices 22 c 1 and 22 c 2 respectively include alaminated of a pair of electrodes and a dielectric film interposedbetween the pair of electrodes, and are connected in series to eachother to constitute the second capacity unit C2. Note that it isunnecessary to provide a plurality of capacitive devices 22 c 1 and 22 c2, and the number of capacitive devices may be one.

Meanwhile, the second pixel circuit 222 includes a plurality of vias 22v 3 and 22 v 4 as interlayer connection portions, a plurality of wiringlayers 22 w 2, and capacitive devices 22 c 3 and 22 c 4.

The vias 22 v 3 pass through the first semiconductor substrate 101 inthe thickness direction via the plurality of wiring layers 22 w 1 or arerouted. The vias 22 v 3 are electrically connected between the onesource/drain area of the transistor (the drive transistor Tr_(Drv) inthe illustrated example) and the vias 22 v 1 of the first pixel circuit221.

The vias 22 v 4 are connected to a gate electrode of the drivetransistor Tr_(Drv) and the other source/drain area.

The capacitive devices 22 c 3 and 22 c 4 respectively include alaminated of a pair of electrodes and a dielectric film interposedbetween the pair of electrodes, and are connected in series to eachother to constitute the first capacity unit C1. Note that it isunnecessary to provide a plurality of capacitive devices 22 c 3 and 22 c4, and the number of capacitive devices may be one.

In the connection area between the vias 22 v 1 and 22 v 3, theconnection points Ct1 and Ct2 for achieving favorable electricalconnection are provided. One connection point Ct1 is provided on thebonding surface 101 b of the first semiconductor substrate 101, and theother connection point Ct2 is provided on the bonding surface 102 a ofthe second semiconductor substrate 102. The connection points Ct1 andCt2 are respectively formed on the same planes as those of the bondingsurfaces 101 b and 102 a, and connected to each other simultaneouslywith the bonding of the bonding surfaces 101 b and 102 a.

The method of bonding the bonding surfaces 101 b and 102 a is notparticularly limited. Typically, a direct bonding method is adopted. Asa result, it is possible to integrally bond the first semiconductorsubstrate 101 and the second semiconductor substrate 102 withoutinterposing an adhesive at the interface.

Examples of the direct bonding include plasma bonding. In the plasmabonding, by forming a silicon-oxygen covalent bond or a silicon-siliconbond between the bonding surface 101 b and the bonding surface 102 a,the bonding surfaces 101 b and 102 a are firmly fixed. As the directbonding, not only the plasma bonding but also a solid-phase bodingmethod such as diffusion bonding may be adopted.

[Method of Producing Display Apparatus]

The display apparatus 100 configured as described above is prepared bybonding (stacking) the first semiconductor substrate 101 and the secondsemiconductor substrate 102 via the bonding surfaces 101 b and 102 a,respectively. FIG. 5A to FIG. 5D are each a schematic diagram describinga method of producing the display apparatus 100.

As shown in FIG. 5A, the first semiconductor substrate 101 including thelight emitting unit 21, the first pixel circuit 221, and the peripheralcircuit area 30 is prepared.

Meanwhile, as shown in FIG. 5B, the second semiconductor substrate 102including the second pixel circuit 222 is prepared.

The connection points Ct1 and Ct2 (see FIG. 4) are respectively formedon a surface S11 a of the first semiconductor substrate 101 and asurface S12 a of the second semiconductor substrate 102.

Subsequently, as shown in FIG. 5C, the upper and lower sides of thefirst semiconductor substrate 101 are reversed, and the surface S11 a isbonded to the surface S12 a of the second semiconductor substrate 102.For bonding, for example, a direct bonding method such as a plasmabonding method is adopted. As a result, the first semiconductorsubstrate 101 and the second semiconductor substrate 102 are integrated,and the first pixel circuit 221 and the second pixel circuit 222 areelectrically connected to each other via the connection points Ct1 andCt2.

Subsequently, as shown in FIG. 5D, a back surface S11 b of the firstsemiconductor substrate 101 is polished to thin the first semiconductorsubstrate 101. Further, after forming, in the first semiconductorsubstrate 101, interlayer connection portions (vias 22 v 1) forelectrically connecting the light emitting unit 21 and the second pixelcircuit 222, the light emitting unit 21 is formed on the firstsemiconductor substrate 101 via an insulation film 21 k (see FIG. 4). Asa result, the display surface 101 a of the display apparatus 100 isprepared.

Note that as necessary, also a back surface S12 b of the secondsemiconductor substrate 102 may be thinned. Further, as the firstsemiconductor substrate 101, a silicon-on-insulator (SOI) substrate inwhich two silicon substrates are stacked with an insulation layersandwiched therebetween may be adopted instead of a single siliconsubstrate.

[Effect]

As described above, in the display apparatus 100 according to thisembodiment, the surface of the first semiconductor substrate 101including the first pixel circuit 221 and the surface of the secondsemiconductor substrate 102 including the second pixel circuit 222 arebonded to each other to constitute the pixel circuit 22. By forming thepixel circuit 22 of originally-separated substrates, i.e., the firstsemiconductor substrate 101 and the second semiconductor substrate 102,the area necessary for forming the pixel circuit 22 is expanded in thethickness direction of the display apparatus 100. Therefore, it ispossible to reduce the area of the pixel area 20 occupying the displaysurface 101 a.

In particular, the organic EL display apparatus needs a relatively highvoltage (Vcc) corresponding to the light emission voltage of the lightemitting device. Therefore, it is necessary to secure at least a certainlength of a gate length of the transistor driving each pixel and atleast a certain distance of device separation for electricallyseparating transistors. In this embodiment, the pixel circuit 22 can bethree-dimensionally routed in the thickness region of the twosemiconductor substrates. Therefore, it is easy to secure at least acertain length of a gate length of the transistor and at least a certaindistance of device separation. As a result, also in the displayapparatus that needs a relatively high voltage, it is possible to reducethe pixel size while securing desired withstand voltage characteristics.

Second Embodiment

FIG. 6 is a schematic side cross-sectional view of main portions of adisplay apparatus 200 according to a second embodiment of the presentdisclosure.

Hereinafter, configurations different from those in the first embodimentwill be mainly described, configurations similar to those in the firstembodiment will be denoted by the same reference symbols, anddescription thereof will be omitted or simplified.

The display apparatus 200 according to this embodiment has a stackedstructure of the first semiconductor substrate 101 and the secondsemiconductor substrate 102. A pixel circuit 420 that drives the lightemitting unit 21 (light emitting device 210) includes a first pixelcircuit 421 formed in the first semiconductor substrate 101, and asecond pixel circuit 422 formed in the second semiconductor substrate102. Similarly to the case of the first embodiment, the peripheralcircuit area 30 is formed in the first semiconductor substrate 101 (seeFIG. 1).

In this embodiment, the configurations of the first pixel circuit 421and the second pixel circuit 422 are different from those in the firstembodiment. Specifically, in this embodiment, the drive transistorTr_(Drv) and the second light-emission-control transistor Tr_(EL_C2) areformed in the first pixel circuit 421, and the image signal writingtransistor Tr_(Sig) and the first light-emission-control transistorTr_(EL_C1) are formed in in the second pixel circuit 222 (see FIG. 6).Note that a pixel circuit 42 is represented by an equivalent circuitsimilar to the pixel circuit 22 in the first embodiment (see FIG. 3).

As shown in FIG. 6, the first pixel circuit 421 includes a plurality ofvias 42 v 1, 42 v 2, and 42 v 3 as interlayer connection portions, and aplurality of wiring layers w1.

The via 42 v 1 connects, via the wiring layer 42 w 1, the anodeelectrode 212 of the light emitting unit 21 and the one source/drainarea of each of the drive transistor Tr_(Drv) and the secondlight-emission-control transistor Tr_(EL_C2).

The via 42 v 2 connects, via the plurality of wiring layers 42 w 1, theother source/drain area of the drive transistor Tr_(Drv) and aconnection point Ct11 on the bonding surface 101 b.

The via 42 v 3 connects, via the plurality of wiring layers 42 w 1, agate electrode 42 g 1 of the drive transistor Tr_(Drv) and a connectionpoint Ct21 on the bonding surface 101 b.

Note that in FIG. 6, the reference symbol 42 g 2 indicates the gateelectrode of the second light-emission-control transistor Tr_(EL_C2).

Meanwhile, the second pixel circuit 422 includes a plurality of vias 42v 4, 42 v 5, and 42 v 6 as interlayer connection portions, a pluralityof wiring layers 42 w 2, the first capacity unit C1, and the secondcapacity unit C2.

The via 42 v 4 connects, via the plurality of wiring layers 42 w 2, theone source/drain area of the image signal writing transistor Tr_(Sig)and a connection point Ct22 on the bonding surface 102 a.

The via 42 v 5 connects, via the plurality of wiring layers 42 w 2, theone source/drain area of the first light-emission-control transistorTr_(EL_C1) and the second capacity unit C2.

The via 42 v 6 connects, via the plurality of wiring layers 42 w 2, thefirst capacity unit C1 and the second capacity unit C2, and a connectionpoint Ct12 on the bonding surface 102 a.

The first capacity unit C1 and the second capacity unit C2 each includea laminate of a pair or electrodes and a dielectric film interposedbetween the pair of electrodes.

Note that in FIG. 6, the reference symbols 42 g 3 and 42 g 4respectively indicated gate electrodes of the image signal writingtransistor Tr_(Sig) and the first light-emission-control transistorTr_(EL_C1).

When the bonding surface 101 b of the first semiconductor substrate 101and the bonding surface 102 a of the second semiconductor substrate 102are bonded to each other, the connection point Ct12 is electricallyconnected to the connection point Ct11, and the connection point Ct22 iselectrically connected to the connection point Ct21. The connectionpoints Ct11 and Ct12 correspond to a node P1 in FIG. 3, and theconnection points Ct21 and Ct22 correspond to a node P2 in FIG. 3.

The display apparatus 200 according to this embodiment configured asdescribed above is prepared by the same way as that in the firstembodiment. Also in this embodiment, the first semiconductor substrate101 may include an SOI substrate.

Also in the display apparatus 200 according to this embodiment, theoperation and effect similar to those in the above-mentioned firstembodiment can be achieved.

In accordance with this embodiment, the peripheral circuit area 30 towhich a relatively high voltage is applied, the drive transistorTr_(Drv), and the second light-emission-control transistor Tr_(EL_C2)are formed in the first semiconductor substrate 101. Therefore, it ispossible to form the image signal writing transistor Tr_(Sig) and thefirst light-emission-control transistor Tr_(EL_C1) to be formed in thesecond semiconductor substrate 102 by a process of lower voltage ascompared with the device to be formed in the first semiconductorsubstrate 101. That is, as compared with the case where there are adevice that needs to have a high isolation voltage in accordance withthe device area and a device that does not need to have a high isolationvoltage in accordance with the device area, it is possible to suppressthe increase in the number of processes due to the difference inthickness of the insulation film, and improve the yield.

Third Embodiment

FIG. 7 is a schematic side cross-sectional view of main portions of adisplay apparatus 300 according to a third embodiment of the presentdisclosure.

Hereinafter, configurations different from those in the secondembodiment will be mainly described, configurations similar to those inthe second embodiment will be denoted by the same reference symbols, anddescription thereof will be omitted or simplified.

The display apparatus 300 according to this embodiment is different fromthe display apparatus 200 according to the second embodiment in that itis formed of two originally-separated substrates, i.e., the firstsemiconductor substrate 101 and the second semiconductor substrate 102,and the first current supply unit 26 and the second current supply unit27 (see FIG. 3) includes a common current supply unit. In thisembodiment, as shown in FIG. 7, a first pixel circuit 521 formed in thefirst semiconductor substrate 101 further includes capacitive devices 52c 1 and 52 c 2 a via 52 v 1.

The capacitive devices 52 c 1 and 52 c 2 are formed in the via 42 v 2 tobe connected to the other source/drain area of the drive transistorTr_(Drv). The capacitive devices 52 c 1 and 52 c 2 each include alaminate of a pair of electrodes and a dielectric film interposedbetween the pair of electrodes, and are connected in series to eachother to constitute the second capacity unit C2 (see FIG. 3).

The via 52 v 1 is branched from the via 42 v 2 in parallel with thecapacitive devices 52 c 1 and 52 c 2. The via 52 v 1 connects the othersource/drain area of the drive transistor Tr_(Drv) and a connectionpoint Ct31 on the bonding surface 101 b.

Meanwhile, a second pixel circuit 522 formed in the second semiconductorsubstrate 102 includes the capacitive devices 52 c 3 and 52 c 4, and theconfigurations of the vias 42 v 5 and 42 v 6 are different from those inthe second embodiment.

The capacitive devices 52 c 3 and 52 c 4 are connected in series to thevia 42 v 6. The capacitive devices 52 c 3 and 52 c 4 each include alaminate of a pair of electrodes and a dielectric film interposedbetween the pair of electrodes, and are connected in series to eachother to constitute the first capacity unit C1 (see FIG. 3).

The via 42 v 5 connects the one source/drain area of the firstlight-emission-control transistor Tr_(EL_C1) and a connection point Ct32on the bonding surface 102 a.

The via 42 v 6 connects the capacitive device 52 c 3 and the connectionpoint Ct12 on the bonding surface 102 a.

When the bonding surface 101 b of the first semiconductor substrate 101and the bonding surface 102 a of the second semiconductor substrate 102are bonded to each other, the connection point Ct12, the connectionpoint Ct22, and the connection point Ct32 are electrically connected tothe connection point Ct11, the connection point Ct21, and the connectionpoint Ct31, respectively.

The display apparatus 300 according to this embodiment configured asdescribed above is prepared by the same way as that in the firstembodiment. Also in this embodiment, the first semiconductor substrate101 may include an SOI substrate.

Also in the display apparatus 300 according to this embodiment, theoperation and effect similar to those in the above-mentioned firstembodiment can be achieved.

In accordance with this embodiment, since the first capacity unit C1 andthe second capacity unit C2 are separately formed in the firstsemiconductor substrate 101 and the second semiconductor substrate 102,respectively, it is possible to reduce the area occupied by the capacityunit as compared with the case of forming a plurality of capacity unitsin the plane. As a result, it is possible to reduce the area of thepixel area to reduce the pixel size, and easily secure the capacitynecessary for the capacity unit.

Further, since the capacity units are formed separately in the pluralityof capacitive devices, it is possible to reduce the electrode area ofeach capacity unit. This has the advantage that the pixel size can befurther easily reduced.

Fourth Embodiment

Subsequently, a fourth embodiment of the present disclosure will bedescribed. FIG. 8 is a schematic side cross-sectional view of mainportions of a display apparatus 400 according to a fourth embodiment ofthe present disclosure.

As shown in FIG. 8, the display apparatus 400 according to thisembodiment includes a first semiconductor substrate 401 and a secondsemiconductor substrate 402, and is configured by bonding (or stacking)the first semiconductor substrate 401 and the second semiconductorsubstrate 402 to each other. Each of the first semiconductor substrate401 and the second semiconductor substrate 402 typically includes asingle crystal silicon (Si) substrate.

In this embodiment, the first semiconductor substrate 401 mainlyincludes a panel-side chip on which a pixel circuit is to be formed, andthe second semiconductor substrate 402 mainly includes a circuit-sidechip on which a peripheral circuit is to be formed.

The first semiconductor substrate 401 includes a pixel area 411, aninterface area 412, connection areas 413 and 414 for connecting to thesecond semiconductor substrate 402, and the like. The interface area 412includes an input/output pad. In the pixel area 411, light emittingunits (light emitting devices) are arranged in matrix for each pixel.

The second semiconductor substrate 402 includes connection areas 421 and428 for connecting to the first semiconductor substrate 401, a DAconverter/amplifier area 422, a horizontal direction scanning circuit423, an interface 424, a gamma voltage generation circuit 425, a memory426, a timing controller 427, a vertical direction scanning circuit 429,and the like.

Since the above-mentioned areas, circuits, and the like formed in thefirst semiconductor substrate 401 and the second semiconductor substrate402 are similar to those in the first embodiment, description thereof isomitted. Further, the layout of the areas, circuits, and the like is notlimited to the form shown in FIG. 8, and can be arbitrarily set.

In accordance with the display apparatus 400 according to thisembodiment, since the pixel area and the peripheral circuit area areseparately formed in the first semiconductor substrate 401 and thesecond semiconductor substrate 402, respectively, it is possible to layout the above-mentioned areas so as to overlap in the thicknessdirection of the display apparatus 400. This makes it easy to reduce thepanel size.

Subsequently, the electrical connection structure of the firstsemiconductor substrate 401 and the second semiconductor substrate 402will be described. The following description can be applied similarly tothe display apparatuses according to the above-mentioned first to thirdembodiments.

FIG. 9A and FIG. 9B are each a schematic side cross-sectional viewshowing an example of the electrical connection structure between thefirst semiconductor substrate 401 and the second semiconductor substrate402. As shown in each figure, the first semiconductor substrate 401includes a substrate body 411, and a wiring layer 412 in which a pixelcircuit and the like are to be formed. Similarly, the secondsemiconductor substrate 402 includes a substrate body 421, and a wiringlayer 422 in which a peripheral circuit and the like are to be formed.FIG. 9A shows the form in which the wiring layer 412 of the firstsemiconductor substrate 401 is bonded to the wiring layer 422 of thesecond semiconductor substrate 402. FIG. 9B shows the form in which thesubstrate body 411 of the first semiconductor substrate 401 is bonded tothe wiring layer 422 of the second semiconductor substrate 402.

In the display apparatus 400 shown in FIG. 9A, a connection point 413 isformed on the surface of the wiring layer 412 of the first semiconductorsubstrate 401, and a connection point 423 is formed on the surface ofthe second semiconductor substrate 402. In this example, the connectionpoints 413 and 423 are configured to be electrically connected to eachother simultaneously with the bonding of the first semiconductorsubstrate 401 and the second semiconductor substrate 402.

Meanwhile, in the display apparatus 400 shown in FIG. 9B, a via(connection hole) 430 that penetrates the substrate body 411 of thefirst semiconductor substrate 401 is formed between the connection point413 formed in the wiring layer 412 of the first semiconductor substrate401 and the connection point 423 formed in the wiring layer 422 of thesecond semiconductor substrate 402. Also in this example, the connectionpoints 413 and 423 are connected to each other when the firstsemiconductor substrate 401 and the second semiconductor substrate 402are bonded to each other. Alternatively, after bonding the firstsemiconductor substrate 401 and the second semiconductor substrate 402to each other, the via 430 and the connection point 413 may be formed.

As shown in FIG. 9A and FIG. 9B, the light emitting unit 21 is formed onthe top surface of the first semiconductor substrate 401. Further, acontrol unit (not shown), an external terminal 414 to be connected to anexternal device or the like, and the like are provided on the topsurface of the first semiconductor substrate 401.

In this embodiment, the connection points 413 and 423 are providedoutside the pixel area (area in which the light emitting unit 21 isformed). However, the present disclosure is not limited thereto, and theconnection points 413 and 423 may be provided immediately below thepixel area (on the central side of the panel). Also the number of theconnection points 413 and 423 is not limited. A plurality of connectionpoints 413 and a plurality of connection points 423 may be arranged onthe corresponding substrate.

Further, as shown in FIG. 10, a pixel area (pixel circuit) 440 may bedivided into two areas 441 and 442 in the vertical direction, and aswitch 460 may switch supply of an image signal or an voltage signalfrom a peripheral circuit 450 to each of the areas 441 and 442. In thiscase, the switch 460 may include the above-mentioned connection points413 and 423, or may be separately provided in the vicinity of theconnection points 413 and 423.

Further, in accordance with this embodiment, since the pixel area andthe peripheral circuit area are formed in different semiconductorsubstrates, it is possible to form, on the same panel, a circuit areaother than the pixel area and the peripheral circuit area. For example,as schematically shown in FIG. 11, in the first semiconductor substrate401, one or more pixels 415 of an image sensor may be arranged aroundthe pixel area 411, and a drive circuit that drives the pixel 415 may bedisposed on the second semiconductor substrate 402. In this case, forexample, it can be applied to pupil position detection of a user in ahead-mounted display.

Alternatively, a different circuit other than the peripheral circuit maybe disposed on the second semiconductor substrate 402. Examples of thedifferent circuit include a super-resolution circuit that increase theresolution of an input image for output, and a circuit for wirelesscommunication with an external device. As a result, the displayapparatus can be sophisticated and multifunctional.

[Embodiment of Electronic Apparatus]

The organic EL display apparatus according to an embodiment of thepresent disclosure is incorporated in, for example, various electronicapparatuses according to application examples 1 to 6 described below.Note that the application examples are not limited thereto. The organicEL display apparatus is applicable to, for example, electronicapparatuses such as a portable information terminal, a smartphone, aportable music player, a game machine, an electronic book, variousdisplay units in an electronic dictionary, and an electronic viewfinder.

Since the organic EL display apparatus according to an embodiment of thepresent disclosure has stable display quality and can achieve highdefinition even in the case where it is miniaturized as described above,it is possible to provide an image with high image quality to a user ofan electronic apparatus in which such an organic EL display apparatus isincorporated.

APPLICATION EXAMPLE 1

FIG. 12 shows an appearance of a television apparatus 500 as anelectronic apparatus. This television apparatus includes, for example, avideo display screen unit 501. The video display screen unit 501includes a front panel 510 and a filter glass 520. The video displayscreen unit 501 includes the display apparatus according to any of theabove-mentioned embodiments.

APPLICATION EXAMPLE 2

FIG. 13 shows an appearance of a digital camera 600 as an electronicapparatus. This digital camera includes, for example, a light emittingunit 610 for flash, a display unit 620, a menu switch 630, and a shutterbutton 640. The display unit 620 includes the display apparatusaccording to any of the above-mentioned embodiments.

APPLICATION EXAMPLE 3

FIG. 14 shows an appearance of a laptop personal computer 700 as anelectronic apparatus. This laptop personal computer includes, forexample, a main body 710, a keyboard 720 for an input operation ofcharacters or the like, and a display unit 730 for displaying an image.The display unit 730 includes the display apparatus according to any ofthe above-mentioned embodiments.

APPLICATION EXAMPLE 4

FIG. 15 shows an appearance of a video camera 800 as an electronicapparatus. This video camera includes, for example, a main body 810, alens 820 for imaging an object, which is provided on the front side ofthe main body 810, a start/stop switch 830 at the time of imaging, and adisplay unit 840. The display unit 840 includes the display apparatusaccording to any of the above-mentioned embodiments.

APPLICATION EXAMPLE 5

FIG. 16 shows an appearance of a mobile phone 900 as an electronicapparatus. This mobile phone is obtained by, for example, connecting anupper housing 910 and a lower housing 920 by a connection portion (hingeportion) 930, and includes a display 940, a sub-display 950, a picturelight 960, and a camera 970. The display 940 or the sub-display 950includes the display apparatus according to any of the above-mentionedembodiments.

APPLICATION EXAMPLE 6

FIG. 16 shows an appearance of a head-mounted display 1000 as anelectronic apparatus. This head-mounted display is obtained by mountingan eyewear-mounting-type one-eye display 1010 on an eyewear 1000 such asglasses, goggles, and sunglasses. The eyewear-mounting-type one-eyedisplay 1010 includes the display apparatus according to any of theabove-mentioned embodiments.

Further, the display apparatus according to any of the above-mentionedembodiments is applicable also to, for example, a VR (Virtual Reality),AR (Augmented Reality), MR (Mixed Reality) head-mounted display asanother form of the head-mounted display.

Embodiments of the present disclosure are not limited theabove-mentioned embodiments, and various modifications can be madewithout departing from the essence of the present disclosure.

For example, although an example in which the transistor is formed onthe silicon semiconductor substrate has been described in theabove-mentioned embodiments, the transistor may be formed on a substrateformed of glass or the like on which a semiconductor film is formed as asilicon area.

Further, although the PMOS in which the conductive type of each of thechannels of various transistors is p-type have been described as anexample in the above-mentioned embodiments, an NMOS in which theconductive type is n-type.

Further, the display apparatus according to an embodiment of the presentdisclosure is applicable to electronic apparatuses such as a monitorapparatus that configures a television receiver or a digital camera, amonitor apparatus that configures a video camera, a monitor apparatusthat configures a personal computer, portable information terminal, amobile phone, a smartphone, a portable music player, a game machine, anelectronic book, various display units in an electronic dictionary, anelectronic view finder, and a head-mounted display.

Further, although an example in which the light emitting unit isconfigured by using an OLED has been described in the above-mentionedembodiments, in addition thereto, a self-luminous light emitting unitsuch as an inorganic electroluminescent light emitting unit, an LED(Light Emitting Diode) light emitting unit, and a semiconductor laserlight emitting unit may be used as the light emitting unit.

Note that, the present disclosure may also take the followingconfigurations.

(1) A display apparatus, including:

a first semiconductor substrate that includes a light emitting unit anda first drive circuit, the first drive circuit driving the lightemitting unit; and

a second semiconductor substrate that includes a second drive circuit tobe electrically connected to the first drive circuit, the secondsemiconductor substrate being bonded to the first semiconductorsubstrate.

(2) The display apparatus according to (1) above, in which

the light emitting unit includes a plurality of light emitting devicesarranged in matrix, and

the first drive circuit is at least a part of pixel circuits thatindividually drive the plurality of light emitting devices.

(3) The display apparatus according to (2) above, in which

the first drive circuit is a part of the pixel circuits, and

the second drive circuit is another part of the pixel circuits.

(4) The display apparatus according to (3) above, in which

the first drive circuit includes a transistor that switches a signalvoltage or a power supply voltage, and

the second drive circuit includes a transistor that controls a currentflowing to the light emitting unit.

(5) The display apparatus according to (4) above, in which

the second drive circuit further includes a transistor that resets avoltage applied to the plurality of light emitting devices.

(6) The display apparatus according to (3) above, in which

the first drive circuit includes a transistor that controls a currentflowing to the light emitting unit, and

the second drive circuit includes a transistor that switches a signalvoltage or a power supply voltage.

(7) The display apparatus according to (6) above, in which

the first drive circuit further includes a transistor that resets avoltage applied to the plurality of light emitting devices.

(8) The display apparatus according to any one of (3) to (7) above, inwhich

the first drive circuit includes a first capacitive device, and

the second drive circuit includes a second capacitive deviceelectrically connected to the first capacitive device.

(9) The display apparatus according to any one of (3) to (7) above, inwhich

the second drive circuit includes a first capacitive device and a secondcapacitive device electrically connected to the first capacitive device.

(10) The display apparatus according to (2) above, in which

the first drive circuit is a pixel circuit that individually drives theplurality of light emitting devices, and

the second drive circuit is a peripheral circuit that supplies a signalvoltage or a power supply voltage to the pixel circuit.

(11) The display apparatus according to any one of (1) to (10) above, inwhich

the first semiconductor substrate and the second semiconductor substrateeach include a substrate body and a wiring layer, and

the wiring layer of the first semiconductor substrate is bonded to thewiring layer of the second semiconductor substrate.

(12) The display apparatus according to any one of (1) to (10) above, inwhich

the first semiconductor substrate and the second semiconductor substrateeach include a substrate body and a wiring layer, and

the substrate body of the first semiconductor substrate is bonded to thewiring layer of the second semiconductor substrate.

(13) A method of producing a display apparatus, including:

preparing a first semiconductor substrate that includes a light emittingunit and a first drive circuit, the first drive circuit driving thelight emitting unit;

preparing a second semiconductor substrate that includes a second drivecircuit; and

electrically connecting the first drive circuit and the secondsemiconductor substrate by bonding the first semiconductor substrate andthe second semiconductor substrate to each other.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A display apparatus, comprising: a firstsemiconductor substrate that includes a light emitting unit and a firstdrive circuit, the first drive circuit driving the light emitting unit;and a second semiconductor substrate that includes a second drivecircuit to be electrically connected to the first drive circuit, thesecond semiconductor substrate being bonded to the first semiconductorsubstrate.
 2. The display apparatus according to claim 1, wherein thelight emitting unit includes a plurality of light emitting devicesarranged in matrix, and the first drive circuit is at least a part ofpixel circuits that individually drive the plurality of light emittingdevices.
 3. The display apparatus according to claim 2, wherein thefirst drive circuit is a part of the pixel circuits, and the seconddrive circuit is another part of the pixel circuits.
 4. The displayapparatus according to claim 3, wherein the first drive circuit includesa transistor that switches a signal voltage or a power supply voltage,and the second drive circuit includes a transistor that controls acurrent flowing to the light emitting unit.
 5. The display apparatusaccording to claim 4, wherein the second drive circuit further includesa transistor that resets a voltage applied to the plurality of lightemitting devices.
 6. The display apparatus according to claim 3, whereinthe first drive circuit includes a transistor that controls a currentflowing to the light emitting unit, and the second drive circuitincludes a transistor that switches a signal voltage or a power supplyvoltage.
 7. The display apparatus according to claim 6, wherein thefirst drive circuit further includes a transistor that resets a voltageapplied to the plurality of light emitting devices.
 8. The displayapparatus according to claim 3, wherein the first drive circuit includesa first capacitive device, and the second drive circuit includes asecond capacitive device electrically connected to the first capacitivedevice.
 9. The display apparatus according to claim 3, wherein thesecond drive circuit includes a first capacitive device and a secondcapacitive device electrically connected to the first capacitive device.10. The display apparatus according to claim 2, wherein the first drivecircuit is a pixel circuit that individually drives the plurality oflight emitting devices, and the second drive circuit is a peripheralcircuit that supplies a signal voltage or a power supply voltage to thepixel circuit.
 11. The display apparatus according to claim 1, whereinthe first semiconductor substrate and the second semiconductor substrateeach include a substrate body and a wiring layer, and the wiring layerof the first semiconductor substrate is bonded to the wiring layer ofthe second semiconductor substrate.
 12. The display apparatus accordingto claim 1, wherein the first semiconductor substrate and the secondsemiconductor substrate each include a substrate body and a wiringlayer, and the substrate body of the first semiconductor substrate isbonded to the wiring layer of the second semiconductor substrate.
 13. Amethod of producing a display apparatus, comprising: preparing a firstsemiconductor substrate that includes a light emitting unit and a firstdrive circuit, the first drive circuit driving the light emitting unit;preparing a second semiconductor substrate that includes a second drivecircuit; and electrically connecting the first drive circuit and thesecond semiconductor substrate by bonding the first semiconductorsubstrate and the second semiconductor substrate to each other.